* Removed RestKit from inheritance hierarchy
* Mappings are implemented as concrete classes
* Mapper is much more flexible & powerful
* Much more robust error handling
* Serialization is reimplemented as an object mapping operation
* Added ability to serialize to JSON natively
* Reworked Core Data integration
* Simplified the codebase substantially
* Updates YAJL Parser not to raise an exception and crash when it encounters invalid JSON. The other parsers need to be aligned with this behavior and the delegate methods updated. See Pivotal Story: https://www.pivotaltracker.com/story/show/11925617
* Added requestDidCancel: delegate invocation for tracking cancellation of requests.
* Ensure that the request queue timer is cleared during indeterminate deferral of request loads.
